Variable-mode information signal reproduction apparatus with tracking control

ABSTRACT

A reproduction apparatus reproduces information signals recorded in a plurality of recording modes having different information sizes of an information signal to be recorded per unit time, discriminates the recording mode of the reproduced information signal, and controls tracking between a recording medium and head in accordance with the discrimination result.

This is a divisional application of application Ser. No. 09/428,651filed Oct. 28, 1999 now U.S. Pat. No. 6,263,148.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information signal reproductionapparatus and, more particularly, to tracking control upon reproduction.

2. Related Background Art

As a conventional apparatus of this type, a digital VTR is known. Inthis apparatus, an image signal is converted into a digital signal, thedigital signal is encoded to compress its information size, and theencoded digital signal is recorded on a magnetic tape while forming alarge number of tracks. Upon reproduction, these tracks are traced by arotary head to reproduce the recorded image signal, and the reproducedimage signal is decoded to expand its information size, thus obtainingan original image. For a digital VTR of this type, in recent years,home-use digital VTR standards called DV format has been proposed.

Of this DV format, in an SD mode, an image signal is converted into adigital signal, its information size is compressed to around ⅙ by atechnique such as the DCT, variable-length coding, or the like, and animage signal for one frame is recorded on 10 helical tracks in case ofNTSC.

By contrast, in order to record an image signal on a magnetic tape for alonger period of time, a recording mode called an SDL mode has also beenproposed. In this mode, a higher compression ratio than the SD mode isset to compress the information size of an image signal to ½, and animage signal for one frame is recorded on five tracks.

As the arrangement of a head for recording/reproducing an image signalin both the SD and SDL modes, the arrangement shown in FIG. 1 may beused.

More specifically, referring to FIG. 1, a magnetic tape T serves as arecording medium, and a rotary drum 101 rotates in contact with themagnetic tape. In FIG. 1, the tape T is wound around the rotary drum 101over a 180° range or larger. A rotary head (HA1) 102 is attached ontothe drum 101. A rotary head (HB1) 103 is attached onto the drum 101 tohave a 180° phase difference from the head (HA1) 102. A head (HB2) 104for the SDL mode is attached in the neighborhood of the head (HA1) 102.

The heads 103 and 104 have the same azimuth angle, and the head 102 hasan azimuth angle different from those of the heads 103 and 104.

FIG. 2 shows tracks formed on the magnetic tape T by the heads shown inFIG. 1 in the respective modes.

In the SD mode, the tape T travels at a predetermined speed S in thedirection of an arrow A, and a recording current is alternately suppliedto the head (HA1) 102 and head (HB1) 103 that trace in the direction ofan arrow H, thereby forming tracks at a rate of two tracks per rotationof the rotary drum 101.

Referring to FIG. 2, HA1, HB1, and HB2 indicate the heads that formedtracks, and F0, F1, and F2 the states of tracking signals superposed onthe recorded signals on the individual tracks.

In the DV format (SD and SDL modes), an image signal undergoes 24/25modulation upon recording to superpose a pilot signal used in trackingcontrol upon reproduction on the recorded signal on each track. FIG. 3shows the frequency components of recorded signals on tracks F0, F1, andF2, and tracks are formed in the order of F0→F1→F0→F2→F0. As shown inFIG. 3, on track F1, a frequency component f1 has a peak, and afrequency component f2 and DC component are suppressed. On track F2, afrequency component f2 has a peak, and a frequency component f1 and DCcomponent are suppressed. On track F0, frequency components f1 and f2,and the DC component are suppressed.

In the SD mode, an image is recorded by forming 10 tracks per frame onthe tape T.

On the other hand, in the SDL mode, although the rotational speed of thedrum 101 is the same as that in the SD mode, the convey speed of thetape T is set at S/2, i.e., half that in the SD mode, and a recordingcurrent is alternately supplied to the head (HA1) 102 and head (HB2)104, thus forming tracks at a rate of one track per rotation of therotary drum 101. At this time, since the track pitch is nearly the sameas that in the SD mode, and the convey speed of the tape is half that inthe SD mode, the track angle becomes slightly different from that in theSD mode.

In the SDL mode, an image signal is recorded by forming five tracks perframe. For this reason, the SDL mode can realize a recording time twicethat in the SD mode.

When an image signal is reproduced from the tape T shown in FIG. 2, animage signal recorded in the SD mode is reproduced by the head (HA1) 102and head (HB1) 103, and an image signal recorded in the SDL mode isreproduced by the head (HA1) 102 and head (HB2) 104. In this case, animage signal is reproduced while controlling tracking between the headsand tracks on the basis of pilot signals superposed upon recording.

As described above, upon reproducing the contents of a tape on which animage signal is recorded in only the SD mode, the head (HA1) 102 andhead (HB1) 103 shown in FIG. 1 need only be used; upon reproducing thecontents of a tape on which an image signal is recorded in only the SDLmode, the head (HA1) 102 and head (HB2) 104 shown in FIG. 2 need only beused.

However, upon reproducing the contents of a tape on which image signalsare recorded in both the SD and SDL modes, as shown in FIG. 2, the threeheads shown in FIG. 1 are required, and the number of heads requiredincreases compared to reproduction of a tape on which an image signal isrecorded in only the SD or SDL mode.

For this reason, such arrangement leads to an increase in cost due torequirements of extra head, rotary transformer, head amplifier, and thelike.

SUMMARY OF THE INVENTION

It is an object of the present invention to solve the aforementionedproblems.

It is another object of the present invention to allow reproduction of asignal from a recording medium on which information signals are recordedin a plurality of different modes, without increasing the number ofheads.

In order to achieve these objects, according to one aspect of thepresent invention, there is provided an apparatus for reproducinginformation signals recorded in a plurality of recording modes havingdifferent information sizes of an information signal to be recorded perunit time, comprising:

reproduction means for reproducing information signals recorded in theplurality of modes from a recording medium;

mode discrimination means for discriminating a recording mode of theinformation signal reproduced by the reproduction means;

tracking means for controlling tracking between the recording medium andthe reproduction means; and

control means for controlling tracking by the tracking means inaccordance with a discrimination result of the mode discriminationmeans.

It is still another object of the present invention to implementsatisfactory tracking control upon reproducing signals from a recordingmedium on which information signals are recorded in a plurality ofdifferent modes.

Other objects and features of the present invention will become apparentfrom the following detailed description of the embodiments taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the arrangement of heads uponrecording/reproducing an image signal in the SD and SDL modes;

FIG. 2 shows tracks formed in the SD and SDL modes;

FIG. 3 is a graph showing the frequency components on the individualtracks;

FIG. 4 is a block diagram showing the arrangement of a digital VTRaccording to an embodiment of the present invention;

FIG. 5 is a view for explaining the reproduction process of an imagesignal in the SD mode by the VTR shown in FIG. 4;

FIG. 6 is a timing chart for explaining reproduction by the VTR shown inFIG. 4;

FIG. 7 is a view for explaining the reproduction process of an imagesignal in the SDL mode by the VTR shown in FIG. 4;

FIG. 8 is a block diagram showing the arrangement of a digital VTRaccording to another embodiment of the present invention; and

FIG. 9 is a timing chart for explaining the reproduction process by theVTR shown in FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the present invention will be described indetail hereinafter with reference to the accompanying drawings.

FIG. 4 is a block diagram showing the arrangement of a digital VTRaccording to the first embodiment of the present invention.

Referring to FIG. 4, a magnetic tape T is formed with tracks, as shownin FIG. 2, and an image signal is recorded on that tape T in the SD orSDL mode.

A head (HA) 2 is attached to a rotary drum 1, and a head (HB) 3 isattached to the rotary drum 1 to have a 180° phase difference from thehead (HA) 2. Note that the head (HA) 2 has the same azimuth angle asthat of the head (HA1) 102 shown in FIG. 1, and the head (HB) 3 has thesame azimuth angle as that of the head (HB1) 103 or head (HB2) 104 shownin FIG. 1. The tape T is wound around the rotary drum 1 over a 180°range or larger.

Amplifiers 4 and 5 respectively amplify reproduced signals output fromthe heads 2 and 3. A switch 6 selects one of the output signals from theamplifiers 4 and 5, and outputs the selected signal to an equalizer 7.The equalizer 7 compensates for deterioration of a reproduced signalupon magnetic recording/reproduction.

A data detection circuit 8 detects an original digital signal from thereproduced signal. A track memory 9 stores a compressed reproduced imagesignal for three frames intact. An error correction circuit 10 correctsany errors in the reproduced signal stored in the track memory 9. An AUXextraction circuit 11 extracts auxiliary data (VAUX data) appended tothe image signal stored in the track memory 9. A mode discriminationcircuit 12 discriminates the recording mode (SD or SDL mode) of thereproduced image signal on the basis of the VAUX data output from theAUX extraction circuit 11. A reproduced signal processing circuit 13decodes the image signal output from the track memory 9 incorrespondence with encoding upon recording, to expand the informationsize of the image signal.

Filters 14 and 15 respectively extract components f1 and f2 of a pilotsignal shown in FIG. 3 from the reproduced signal output from theequalizer 7. Switches 16 and 17 respectively select and output one ofsignals of the frequency components f1 and f2 obtained by the filters 14and 15. Detecting circuits 18 and 19 respectively detect the levels ofpilot signals output from the switches 16 and 17. A subtraction circuit20 calculates the difference between the outputs from the detectingcircuits 18 and 19. A switch 21 outputs an output from the subtractioncircuit 20 to a loop filter 22 in accordance with a control signal froma tracking timing control circuit 28. The loop filter 22 filters theoutput from the subtraction circuit 20 obtained via the switch 21 togenerate a tracking error signal (ATF error signal), and outputs thatsignal to a capstan control circuit 23.

The capstan control circuit 23 controls a capstan motor 24 in accordancewith the tracking error signal from the loop filter 22 and recordingmode information from the mode discrimination circuit 12. The capstanmotor 24 controls driving of a capstan to convey the tape T inaccordance with the control signal from the capstan control circuit 23.A PG generation circuit 25 generates a PG signal indicating the rotationphase of the drum 2 in correspondence with rotation of the rotary drum2. A switch pulse generation circuit 26 generates a head switch pulseserving as a switching signal for the switch 7 so as to select one ofthe reproduced signals from the head (HA) 2 and head (HB) 3 inaccordance with the PG signal from the PG generation circuit 25. Aswitch 27 outputs the output signal from the equalizer 7 to the datadetection circuit 8. The tracking timing control circuit 28 controls theswitches 16 and 17, and the switches 21 and 27, in accordance withrecording mode information from the mode discrimination circuit 12 andthe head switch pulse from the switch pulse generation circuit 26.

The reproduction process of a signal by the apparatus shown in FIG. 4will be explained below.

Upon receiving a reproduction start instruction from a console (notshown), the capstan control circuit 23 controls the capstan motor 24 toconvey the tape T at a predetermined speed, and the rotary drum 1 isrotated at a predetermined speed by a drum motor (not shown). The heads2 and 3 alternately trace the tape T to reproduce a signal recorded onthe tape T, and output the reproduced signal to the equalizer 7 via theamplifiers 4 and 5 and switch 6.

The switch 6 is switched between terminals A and B in accordance withthe head switch pulse from the switch pulse generation circuit 26, andoutputs one of the reproduced signals from the amplifiers 4 and 5 to theequalizer 7. The equalizer 7 compensates for deterioration of thereproduced signal due to magnetic recording/reproduction, shapes itssignal waveform, and outputs the processed signal to the data detectioncircuit 8 via the switch 27 and also to the filters 14 and 15.

The data detection circuit 8 detects original digital data from thereproduced signal using a detection method such as integral detection,Viterbi decoding, or the like, and outputs the detected digital data tothe track memory 9. The track memory 9 has a capacity capable of storingthe compressed signal for three frames output from the data detectioncircuit. The error correction circuit 10 corrects any errors in thereproduced image signal stored in the track memory 9 using parity dataappended upon recording, and writes corrected data in the track memory 9again. Note that the operation of the switch 27 will be explained later.

The AUX extraction circuit 11 detects VAUX data appended to the imagesignal from the reproduced signal stored in the track memory 9, andoutputs the detected data to the mode discrimination circuit 12. Themode discrimination circuit 12 detects mode identification dataindicating a recording mode from the VAUX data output from the AUXextraction circuit 11, discriminates the recording mode of thereproduced image signal on the basis of the mode identification data,and outputs recording mode information to the reproduced signalprocessing circuit 13, capstan control circuit 23, and tracking timingcontrol circuit 28.

The reproduced image signal that has undergone the error correctionprocess is output to the reproduced signal processing circuit 13. Thereproduced signal processing circuit 13 decodes the reproduced imagesignal in correspondence with encoding upon recording in accordance withthe recording mode information from the mode discrimination circuit 12,and outputs the decoded signal to an output circuit 29. The outputcircuit 29 converts the reproduced image signal into a format suitablefor an external device, and outputs the converted signal.

The operation upon tracking control in the apparatus shown in FIG. 4will be explained below.

The reproduced signal output from the equalizer 7 is output to thefilters 14 and 15. The filters 14 and 15 respectively extract pilotsignals of frequencies f1 and f2 shown in FIG. 3 from the reproducedsignal, and output the extracted signals to the detecting circuits 18and 19 via the switches 16 and 17. The detecting circuits 18 and 19detect the levels of the pilot signals output from the switches 16 and17, and output the detected levels to the subtraction circuit 20. Thesubtraction circuit 20 calculates the difference between the outputlevels from these detecting circuits 18 and 19 (in this embodiment, theoutput from the detecting circuit 19 is subtracted from that from thedetecting circuit 18, but it may be vice versa), and outputs thedifference to the loop filter 22 via the switch 21.

The loop filter 22 determines the loop gain of the tracking control loopconsisting of the heads 2 and 3, amplifiers 4 and 5, equalizer 7,filters 14 and 15, detecting circuits 18 and 19, subtraction circuit 20,loop filter 22, capstan control circuit 23, and capstan motor 24. Theloop filter 22 filters the output from the switch 21, and outputs thefiltered signal to the capstan control circuit 23.

In this embodiment, each of the heads 2 and 3 has a width slightlylarger than that of each track formed on the tape. For example, when thehead traces track F0, pilot signals of frequencies f1 and f2 leak fromtwo neighboring tracks having different azimuth angles, i.e., tracks F1and F2, into the reproduced signal from track F0.

The capstan control circuit 23 outputs a control signal to the capstanmotor 24 so that pilot signals of frequencies f1 and f2, which arecontained in the reproduced signal from track F0 upon tracing track F0and are detected by the filters 14 and 15, have the same level, i.e.,the head 2 normally scans track F0, thus controlling travel of the tapeT.

More specifically, tracking control is done so that the loop filter 22outputs zero level.

As can also be seen from FIG. 2, in this embodiment, tracks are formedon the tape T in the order of F0→F1→F0→F2→F0. For this reason, thepositions of tracks F1 and F2 that neighbor track F0 are reversed inunits of tracks. Hence, when the outputs from the filters 14 and 15 aredetected and the detected signals are directly output to the subtractioncircuit 20, the sign of the output from the subtraction circuit 20 isinverted in units of tracks, and the direction (phase) of trackingcontrol is reversed between the lead and lag directions.

For this reason, the tracking timing control circuit 28 controls theswitches 16 and 17 to alternately select the outputs from the filters 14and 15 every other tracks, and output them to the detecting circuits 18and 19, thereby preventing the sign of the output from the subtractioncircuit 20 from being inverted.

As described above, the pilot signals of frequencies f1 and f2 aresimultaneously obtained only when track F0 is traced. When track F1 orF2 is traced, only a pilot signal of frequency f1 or f2 is obtained.

In this embodiment, the tracking timing control circuit 28 controls theswitch 21 to output the output from the subtraction circuit 20 to theloop filter 22 only when the head 2 traces track F0. The control processof the switch 21 varies depending on whether the recording mode of thereproduced is the SD or SDL mode, and will be described later.

The tracking timing control circuit 28 controls the switches 16 and 17on the basis of the head switch pulse from the switch pulse generationcircuit 26, and also controls the switches 21 and 27 on the basis of therecording mode information from the mode discrimination circuit 12 andthe head switch pulse.

The tracking control process when the recording mode of the reproducedsignal is the SD mode and that when it is the SDL mode will be explainedbelow.

FIG. 5 illustrates the state wherein tracks formed in the SD mode shownin FIG. 3 are traced by the heads 2 and 3 shown in FIG. 4.

When the mode discrimination circuit 12 detects a mode signal indicatingthe SD mode from the VAUX data, the capstan control circuit 23 controlsthe capstan motor 24 to convey the tape T at a predetermined speed S.

When the recording mode is the SD mode and tracking is normal, theinrush positions of the heads are as indicated by HA and HB in FIG. 5,and the heads 2 and 3 can normally trace the individual tracks, as shownin FIG. 5.

For this reason, a signal having a sufficient level is reproduced fromeach track in units of traces. Hence, the tracking timing controlcircuit 28 turns on the switch 21 at a timing indicated by Tr in FIG. 5,i.e., the timing at which the head 2 is tracing track F0, in the SDmode, thus outputting the output from the subtraction circuit 20 to theloop filter. In the SD mode, the circuit 28 keeps the switch 27 ON.

FIG. 6 is a timing chart of the respective units in the SD mode.

Referring to FIG. 6, a waveform (a) indicates a head switch pulse signalfrom the switch pulse generation circuit 26. The tracking timing controlcircuit 28 turns on the switch 21 at the timing at which the head (HA) 2is tracing the tape T in synchronism with the switch pulse, as indicatedby a waveform (c). In the SD mode, a reproduced signal with a sufficientlevel can be obtained in units of traces of each head, as indicated by awaveform (b).

The control process in the SDL mode will be explained below.

FIG. 7 shows the state wherein tracks formed in the SDL mode shown inFIG. 3 are traced by the heads 2 and 3 shown in FIG. 4.

When the mode discrimination circuit 12 detects a mode signal indicatingthe SDL mode from the VAUX data, the capstan control circuit 23 controlsthe capstan motor 24 to convey the tape T at a predetermined conveyspeed S/2.

When a signal recorded in the SDL mode is reproduced, the rotationalspeed of the drum 1 in FIG. 4 is the same as that in the SD mode, butthe convey speed of the tape T is ½ that in the SD mode. For thisreason, the inrush positions of the heads 2 and 3 with respect to thetracks are as shown in FIG. 7.

Since tracks HA1 and HB2 have different azimuth angles, a signal ontrack HB2 cannot be reproduced by the head (HA) 2, and a signal on trackHA1 cannot be reproduced by the head (HB) 3. Hence, the level of thereproduced signal from the switch 6 is as indicated by a waveform (d) inFIG. 6, and a reproduced signal having a sufficient level can beobtained from the head 2 once (period t1 or t5) per two traces, i.e.,two rotations of the drum 1.

Also, as can be seen from FIG. 7, track HB2 is track F1 or F2, and nopilot signals can be obtained from the two neighboring tracks.

When the switch 21 is turned on for each trace of the head 2 as in theSD mode, a reproduced signal with a sufficient level cannot be obtainedduring periods t3 and t7 in which the head 2 is tracing track HB2, andno pilot signal components can be obtained from the two neighboringtracks. For this reason, when the output from the subtraction circuit 20is supplied to the loop filter 22 during these periods t3 and t7, wrongtracking control may be made.

In this embodiment, the tracking timing control circuit 28 turns on theswitch 21 at a timing indicated by Tr in FIG. 7, i.e., once per twotraces of the head 2, only a satisfactory tracking error signal issupplied to the loop filter 22. In the SDL mode, the tracking timingcontrol circuit 28 turns on the switch 21 once per two periods of thehead switch pulse on the basis of the head switch pulse, as indicated bya waveform (e) in FIG. 6.

As described above, in this embodiment, when the tracking timing controlcircuit 28 turns on the switch 21 once per two traces of the head 2, atracking error signal having a sufficient level can be obtained, andtracking control can be made to make the head 2 normally trace track F0.Since the track angle is slightly different from that in the SD mode butthe track pitch is nearly the same as that in the SD mode, a signalhaving a sufficient level can be reproduced by the head 2 from roughlythe entire area of track F0, as indicated by the waveform (d) in FIG. 6.

The hatched portions in the waveform (d) in FIG. 6 correspond to periodsin which the head 2 is tracking track HB2. During these periods, sincetrack HB2 and the head 2 have different azimuth angles, no signal with asufficient level can be obtained from the head 2. For this reason, thetracking timing control circuit 28 turns off the switch 27 during thehatched periods in the waveform (d) in FIG. 6, i.e., periods in whichthe head 2 is tracing track HB2, on the basis of the head switch pulse,thus inhibiting the reproduced signal from the head 2 from being outputto the track memory 9.

The reproduced signal from the head 3 has a level which is high enoughto make the data detection circuit 8 detect original digital data,although the level is slightly smaller than that in the SD modeindicated by the waveform (b) in FIG. 6, as indicated by the waveform(d) in FIG. 6.

In this manner, in this embodiment, since the tracking error signalextraction timing is changed in correspondence with the SD and SDLmodes, a signal recorded in the SDL mode can be reproduced using onlythe heads 2 and 3 corresponding to the SD mode.

For this reason, signals recorded in the SD and SDL modes can bereproduced without adding any dedicated SDL head shown in FIG. 1, and anincrease in cost of the apparatus can be suppressed.

The second embodiment of the present invention will be described below.

In the above embodiment, since each head has a width slightly largerthan the track width, and tracking control is made to obtain areproduced signal with a sufficient level from the head 2 over nearlythe entire area of the track upon reproduction in the SDL mode, the head3 traces across two tracks, i.e., tracks HA1 and HB2.

For this reason, the reproduced signal from the head 3 has a level lowerthan that from the head 2. Although the data detection circuit 8 candetect original digital data from the reproduced signal from the head 3,the number of errors in the reproduced signal from the head 3 may becomelarger than that in the reproduced signal from the head 2.

To solve this problem, in this embodiment, a tracking error signal isoffset so that the head 3 traces either track F1 or F2.

FIG. 8 is a block diagram showing the arrangement of a digital VTR inthis embodiment, and a description of the same arrangement as that inFIG. 4 will be omitted.

Referring to FIG. 8, a multiplication circuit 30 multiplies the outputfrom the detecting circuit 18 in accordance with recording modeinformation from the mode discrimination circuit 12.

That is, when the recording mode is the SD mode, the output from thedetecting circuit 18 is directly output to the subtraction circuit 20.On the other hand, when the recording mode is the SDL mode, the outputfrom the detecting circuit 18 is multiplied by a predeterminedcoefficient to control the balance between the levels of the pilotsignals from the filters 14 and 15, thereby offsetting a tracking errorsignal so that the head 3 traces track HB2.

More specifically, an offset for delaying the phase of a tracking errorsignal is given so that the head (HB) 3 traces track F1 at, e.g., atiming indicated by “OFFSET” in FIG. 7.

FIG. 9 is a timing chart in the SDL mode when such offset is given.

As can be seen from a waveform (b) in FIG. 9, the reproduced signallevels during periods t2 and t6 become higher than those in the firstembodiment indicated by the waveform (d) in FIG. 6. Hence, errors insignals reproduced during these periods can be fewer than those in thefirst embodiment.

On the other hand, the reproduced signal levels during periods t4 and t8in the waveform (b) in FIG. 9 are lower than those in the waveform (d)in FIG. 6, since the tracking error signal is shifted to make the head 3trace track HB2 during the periods t2 and t6. However, the reproducedsignal obtained during the period t4 is a signal reproduced from thesame track as that obtained during the period t2, and the reproducedsignal obtained during the period t8 is a signal reproduced from thesame track as that obtained during the period t6. For this reason,satisfactory reproduced signals can be obtained from all the tracks.

In this way, in this embodiment, since the tracking error signal isshifted to make the head 3 trace track HB2, the number of errors in thereproduced signal from track HB2 can be reduced.

As described above, in each embodiment of the present invention, uponreproducing image signals recorded in the SD and SDL modes havingdifferent recorded information sizes per unit time from a tape, sincethe tracking error signal extraction timing (pilot signal extractiontiming) is switched in accordance with the recording mode of thereproduced image signal, image signals recorded in the SD and SDL modecan be satisfactorily reproduced by a common head arrangement.

In the VTR shown in FIG. 4 or 8, some or all process that pertain to thetracking control may be implemented by software using a microcomputerand memory. In this case, the memory stores a program for implementingthe aforementioned tracking control.

As this storage medium, a semiconductor memory such as a ROM, RAM, orthe like, optical disk, magnetooptical disk, magnetic recording medium,and the like may be used, and they may form a CD-ROM, floppy disk,magnetic card, magnetic tape, nonvolatile memory card, and the like.

Many widely different embodiments of the present invention may beconstructed without departing from the spirit and scope of the presentinvention. It should be understood that the present invention is notlimited to the specific embodiments described in the specification,except as defined in the appended claims.

1. An apparatus for reproducing information signals recorded in aplurality of recording modes each having different amounts ofinformation of information signals to be recorded per unit time, saidapparatus comprising: a reproduction unit configured to reproduceinformation signals recorded in the plurality of modes from a recordingmedium, with only two reproduction heads having different azimuthangles, respectively; a mode discrimination unit configured todiscriminate a recording mode of the information signal reproduced bysaid reproduction unit; a tracking unit configured to control trackingbetween the recording medium and said reproduction unit and informationindicating a relationship between a track on the recording medium andthe azimuth angles of the reproduction heads; a control unit configuredto control a tracking control procedure by said tracking unit indifferent manners in accordance with a discrimination result of saidmode discrimination unit; a memory unit configured to store theinformation signal reproduced by said reproduction unit; and a memorywriting unit configured to write the information signal reproduced bysaid reproduction unit into said memory unit in different manners inaccordance with the discrimination result of said mode discriminationunit and information indicating a relationship between a track on therecording medium and the azimuth angles of the reproduction heads.